Preparation of dinitroparaffins



Patented May 10, 1949 OFFICE PREPARATION OF DINITROPARAFFINS John H. McCracken, Cumberland, Md.,

and

George S. Crandall, Woodbury, N. J., assignors to Socony-Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application January 29, 1946, Serial No. 644,196

.6 Claims.

This invention has to do with a new method for the preparation of gem-dinitroparafiins and, more particularly, has to do with a new method for the preparation of those gem-dinitroparamns which are characterized by attachment of both nitro groups to a secondary carbon atom.

In the past, several attempts have been made to prepare gem-dinitroparafiins of the type represented by the following general formula:

R'/ \NO2 wherein R and B may be the same or different alkyl groups. All previous attempts, however, have been occasioned by little success, inasmuch as the starting materials or reactants have been relatively expensive, the yields of the desired products have been small, etc., and, in general, all of such methods have provcn uneconomical. For example, ter Meer (Liebigs Annalen der Chemie, 181, 1, (1876)) and Nef (ibid. 280, 263 (1894)) prepared secondary gem-dinitroparaffins by reaction of an alkyl halide with a silver salt of a primary gem-dinitroparafiin. J. Bredt (Berichte, 15, 2318 (1882)) reported that a small amount of 2,2-dinitropropane was obtained when isovaleric acid was nitrated at C. The same dinitropropane was also prepared in rather small yields by Meyer and Locher (Annalen 180, 133 (1876)) by an oxidation method, chromic acid being added to oxidize propyl pseudonitrole in acetic acid solution. The highest yield of the aforesaid dinitropropane obtained by Meyer and Locher was 35%; however, they were not able to ropes-t this performance consistently. Meyer and Locher also reported that a small yield, 17%, of the same dinitropropane was obtained when propyl pseudonitrole was heated near its melting point.

We have now discovered an inexpensive method whereby substantial yields of secondary gemdinitroparafiins are obtained. Specifically, the present method involves contacting a pseudonitrole with nitrogen tetroxide (N204 or N02) at a temperature up to about C. above the decomposition temperature of the pseudonitrole.

The pseudonitroles contemplated herein for conversion to their corresponding gem-dinitroparaflins are represented by the general formula:

wherein R and B may be the same or different alkyl groups and may be unsubstituted or substitutcd with such substituents as halogen, nitro, aryl, etc. While all of the pseudonitroles so defined are contemplated for use, propyl pseudonitrole, which is converted herein to 2,2-dinitropropane, is particularly preferred. The pseudonitroles may be prepared by any of the methods well known in the art. However, an inexpensive and preferred method is that which is described in Patent No. 2,370,185 issued on February 27', 1945 to E. M. Nygaard, J. H. McC'racken and T. T. Noland.

In the present process, the reaction temperature may be varied considerably up to about 10 C. above the decomposition temperature of the pseudonitrole reactant. As indicated hereinafter, by way of illustration, temperatures as low as 10 C. to 50 C. are suitable for converting propyl pseudonitrole to 2,2-dinitropropane. Temperatures up to about 85 C. are those which are to be used for the foregoing conversion, inasmuch as the decomposition temperature of propyl pseudonitrole is C.

In order to illustrate the present invention, a typical and preferred gem-dinitroparafiin-2,2- dinitropropanewas prepared as described in detail in the following examples:

Example I Example II Liquid nitrogen tetroxide, about 75 parts by weight, was placed in a glass beaker in an ice bath. The nitrogen tetroxide was stirred by a mechanical stirrer and maintained at approximately 0 C. by means of the ice bath. Propyl pseudonitrole, about 30 parts by weight, was added in small quantities to the nitrogen tetroxide over the period of 5 hour. Additional nitrogen tetroxide approximately 35 parts by weight was added as additional solvent. Mixture was main- The ; 5 tained; at a: temperature of; 6+5; (3; :ior: 1: hour; 5 mixtureicontainingi said; dihitroparaffin is forme 5 hen allowed. :to; warmi up: slowly to: approru r and separatingsaid: dinitroparazffinrfrom; said I mate1y;25-: C.- :at which time: substantialiy a1i= oi; action: mixture; 5 a 1 5 I 1 thezsoiid :had dissoived or reacts f The. reaction '3; :The method preparatiori product was isolateci by 5 ifstfiiiet n or the ease; ei5n5-dinitroparaffin which com'prgises;; oointaetin' oxide of; nitrogen; and steam distiilatien; of5 res; 5 a monomeric lower alkyl pseudonitroieat; a; tem dual; product whereupon 12 parts :by weight: oi i perature :up: to about 1 0 :(3: above iitS oiecomposi 2;,2;-dinitrcpropane were: obtained tion temperature-with nitrogen :tetroxide,=where: sperms its a yield of 36%;; 5 5 5 5 5 5 by; a reaction: mixture containing said flinitr 1 I51: wiilibje apipa'rientfroin? the foregoing i lustre c: p r ffin r i form an separatin Said: i iti" tive;examples that the piesentmethod is :a:va1u-: Qaraffin from Sam reacticnmixture able means for: preparing secondary gemdinitro paraffins. ;As is welikncwn to those: familiar with :the che'm'ic ai ;a'.rt; siich compounds: are: valuable intermediatesfinichemical synthesis: and recent 1v these: compounds have 5 been-l fiJ Uillfi to: be, :ex c ntainin i in:itr hmpa ie :is :ferme 5 i and v tremely efiie 5 separating said? 2i,2 i-:iinitroprojpane from saidire- .vfliuel's'.iviv "":actionmixture.z:-:::;;;:::::;:;:;

' 5 iAishough the: hrieseri invention: has been 511mg 5.: 'Ihe: method :of preparation: of: 2g2-dihitrmtrat ec'i hsreinahove b :the: preparation; of a spe r p znowhich: comp i s,:contacting'propm pse oific seeenaery: eemsdinitroparafiin' :an'oi has; bee illustrated by specific procedures, This to 'h e:11n der'-; stood that :these: are gbut preferred embodiment of this new: method: for the preparation :of sec .ondary gem-i-dihitropaiafihs'; T The present V5611. 5 hone; however; is not, to :be: construed I as: limited: 5 thereto; but to be broadly construed in the: iigh Oiithei defi g A; The method :of 5 preparation {if 2g2 dinitro propanewhich:comprisesgcontaeting: propyi pseu' onitroie: eta temperature up to about 85? C; with itrogen tetroxide; whereby a reaction :mixture whereby a reaction mike 32: tfintaiirii'ig 2g2 dinhtropropane: :is: formed; anfi ;-sepairating isaid 2;,

' tmhrwane. from: said reaction-mixtwe- 6.: The method :of prepara'tihh o fi 2, 2'- dihit1 pseudonitroie: at: about: 89;" C; with: nitrogen 5 tetroxide and carbon tetrachloride; whereby a r 2 action mixture 3 containing i2;2+ciirritroprop'ane seucionitrcie at: a tem. we e: wz be rw Q 5 9mm 5 ion: temperature :Wit nitrogen: t-etr (168,; s pseuolonitrolehavingthe generalformula-r 5 5 49 Rheinboidt, Ba-1cm dutsche' criern GselLQ R NO v01. 60 (1927), pages 250-51.

\/ Scholl, Berichte deutsche chem. GeselL, v01. 23 (1890) pages 3490-3495.

Meyer et a1., Liebigs Annalen, Vol. 180 (1875) wherein R and R are as defined above. 45 page 144 and page 147.

2. The method of preparation of a secondary Charlton et a1., Jour chem. 800., (London) gem-dinitroparafiin which comprises, contacting 1932, page 36. a lower alkyl pseudonitrole at a. temperature up Ponzio, Gazz. Chim. Ital. Vol. 27 (1897),pages to about 10 C. above its decomposition tempera- 271-275. ture with nitrogen tetroxide, whereby a reaction 50 

